This invention relates to a filter for determining cross-correlation, to a receiver with a correlation circuit, and to a method of equalizing signals as set forth in the preambles of the independent claims.
Various receivers for optical signals with input filters and control systems for parameters of the input filters are known in the art. In an article by H. Bülow, NOC '97, Antwerp 1977, “Equalization of Bit Distortion Induced by Polarization Mode Dispersion”, various filters, so-called equalizers, are used for conditioning optically transmitted signals.
The as yet unpublished Patent Application DE 198 21 142.2 discloses on optical receiver for the reception of digitally transmitted data. In this receiver, a simple transversal equalizer structure is proposed which works even at very high bit rates. The setting parameters for the transversal filter are generated by evaluating a pseudo-error monitor. The object of the present invention is to provide an optical receiver for high bit rates (40 Gb/s) which contains circuits that are well suited for integration and thus can be manufactured at low cost.